1. Field of the Invention
The present invention is directed generally to: mounting systems for screen assemblies used in vibratory separators; such screen assemblies; vibratory separators and shale shakers; in one particular aspect to a selectively operable powered system for holding and clamping screen assemblies in shale shakers used for treating drilling fluids; and methods of use of these things.
2. Description of Related Art
The prior art discloses a variety of vibratory separators and shale shakers. Vibratory separators are used in a wide variety of industries to separate materials such as liquids from solids or solids from solids. Typically such separators have a basket or other screen holding or mounting apparatus mounted in or over a receiving receptacle or tank and vibrating apparatus for vibrating the basket. One or more screens is mounted in the basket. Material to be treated is introduced to the screen(s) either by flowing it directly onto the screen(s) or by flowing it into a container, tank, or “possum belly” from which it then flows to the screen(s). Also in some multi-screen apparatuses material flows from an upper screen onto a lower screen.
The prior art discloses a variety of mounting systems and apparatuses for releasably mounting a screen assembly to a shale shaker. These include drawbar and hookstrip apparatuses; inflatable device systems; wedge systems; e.g. the systems described in U.S. Pat. No. 6,179,128 issued Jan. 30, 2001; U.S. Pat. No. 5,392,925 issued Feb. 28, 1995; U.S. Pat. No. 4,882,054 issued Nov. 21, 1989; U.S. Pat. No. 4,582,597 issued Apr. 15, 1986; and in the prior art referred to in each of these references.
Referring now to FIG. 5, a prior art shale shaker 1 has a screen 2 (with screen or screening cloth or mesh as desired) mounted on vibratable screen mounting apparatus or “basket” 3. The screen 2 may be any known screen or screens. The basket 3 is mounted on springs 4 (only two shown; two as shown are on the opposite side) which are supported from a frame 6. The basket 3 is vibrated by a motor 5 and interconnected vibrating apparatus 8 which is mounted on the basket 3 for vibrating the basket and the screens. Elevator apparatus 7 provides for raising and lowering of the basket end.
FIG. 6 discloses an example of a prior art shaker system (e.g. as shown in U.S. Pat. No. 5,190,645 incorporated fully herein for all purposes). The system A has a shale shaker K having a screen or screens S. The screen(s) S are mounted in a typical shaker basket B and one or more vibrators V (any known suitable shaker vibrator) vibrate the basket B and hence the screen(s) S. The other components of the system A are as described in U.S. Pat. No. 5,190,645.
The prior art discloses a variety of screen assemblies and of screen assembly mounting systems for holding screen assemblies in vibratory separators, for releasably clamping such screen assemblies in position, for maintaining such screen assemblies in position during operation of the separators, and, in certain apparatuses, for providing desired tension on screening material that is part of a screen assembly. Since the screening material of these screen assemblies wears, tears, and degrades during use, it is desirable that the screen assembly mounting systems provide for easy installation, removal, and replacement of screen assemblies.
U.S. Pat. Nos. 3,968,033; 4,846,352; 5,226,546; 4,224,146; 4,744,898; 6,179,128; 4,040,951; 4,303,509; 5,332,101; 6,401,935; 3,718,963; and 2,630,225 (all incorporated fully herein) and the references cited ther in provide a variety of separators, shakers, and mounting systems for screen assemblies therein.
There has long been a need, recognized by the present inventors, for a fast and efficient way to replace screen assemblies in a vibratory separator or shale shaker. There has long been a need, recognized by the present inventors, for a way to change out a screen assembly without shutting down a wellbore operation which employs the separator or shaker. There is a need, recognized by the present inventors, for an efficient and effective screen mounting structure and method for screen assemblies for shale shakers. There is a need, recognized by the present inventor, for an efficient and stable mounting of screens to a shale shaker.